Method and means for electrodepositing nickel metals and the resulting products



Patented Nov. 23, 1926.

UNITED STATES PATENT oFFics l- CHARLES P. M ADSEN, OF NEW YORK, N. Y., ASSIGNOR TO MADSENELL CORPORATION,

OF NEW YORK, N. Y., A CORPOEATION OF NEW' YORK.

METHOD AND JVLEANS non nnncrnonnrosrrrrno NICKEL METALS AND THE ransom,- ING PRODUCTS.

No Drawing. Application filed June as. 1923. Serial n6. 647,912, Renewed June 4, 1926.-

My present invention relates to methods and means for electrodepositing nickel metals, by which I mean to designate nickel, or cobalt, or alloys high in nickel or in cobalt or in both of-these metals, particularly certain electrolytic or electrically deposited alloys of a nickel metal, such as nickel and iron, especially such alloys containing substantial percentages of iron. My invention relates also to the resulting metal products.

It is an object of the present invention to devise methods and means of the general character referred to above which shall enable t-he electrodeposition of the metals and metal alloys previously designated, particularl y the nickel nietal-iron, such as nickeliron alloys referred to above.

iron, alloys referred to'above, in a mechani cally perfect condition, that 1s, 111 a conditzon in which these elcctrodeposited metals and metal alloys shall be substantially free from pores, pits, bunkles, and other mechanical imperfections, while at the same time possessing certain other very desirable properties hereinafter set forth in detail.

While the principles of the present invention are applicable with considerable success to the electrodeposition of sul'istantially pure nickel metal, such as nickel, substantially in the form described and claimed in one of my pending applications l'iearing Serial No. 292,794, filed April 26, 1919, and entitled Electrodeposited metals, in the form which contains only a trace "or other negligible amount of iron, or hydrogen, or of both of these elements, it finds even more successful application, constituting perhaps its most successful application, in the production of the nickel metal-iron, such as the nickel- This new form of electrodeposited nickel metal-iron, such as nickel-iron alloy, while being mechanicallyperfect, in the sense in wh ch this term has been defined above, in that it is substantially free from pores, pits, bunkles and other mechanical imperfections, like the earlier form of substantially pure electrodeposited nickel metal, such as nickel described and claimed in the pending application already identified, differs from this earlier 1 form in that it is considerably stronger and harder than the latter variety of my mechanically perfect el-ectro'deposited nickel metal, such as nickel. This latter variety 1 term the soft variety. My new form of electrodeposited nickel metal-iron, such as nickel-iron alloy, is somewhat less ductile and shows a tendency to become cold-short or slightly brittle after annealing or other heat treatment, as distinguished from the soft variety of my metal, which latter is remarkably ductile and free from any tendency to become cold-short or slightly brittle after annealing or other heat treatment. This new variety of electrodeposited mechanically perfect nickel metal or nickel metal-iron, such as nickel-iron alloy, I term the hard variety.

In the accompanying specification I shall describe illustrative en'ibodimeiits of the method, means and product of the present invention. It is, however, to be clearly understood that my invention is not limited to the specific embodiments thereof herein described for purposes of illustration only. Referring now to the aforesaid illustratlve embodiments of the present invention, and moie particularly to the method itself, the latter may be described as follows: F or the electrodeposition bat-h I prefer to use a nickel bath containing a fluorine compound, preferably a compound-of nickel and fluorine, such as acid nickel fluoride, or nickel fluoro borate. I find, that this fluoride bath, especially when combined with the other features of the present invention, gives a superiorresult in operation and a better final product. 1

For practical purposes it is not desirable to operate a bath containing either of these salts or compounds alone. Instead of this, the metal content of the bath is preferably made up of a solution of nickel sulphate, iii the proportion, preferably, of 300 grammes per liter, to which about 10%, by Weight, of

either of the fluorine compounds designated above is added, calculated on the basisof the Weight of the nickel sulphate containing the usual Water of crystallization (Ni SO ,7H O) used in the bath.

I have discovered that a nickel metal detail herein, and in order also, to avoid the formatlon of pits and similar meehanlcal 1mperfect-ions in the resulting electrodeposited metal, should be substantially. free from ferric compounds, particularly such compounds in solution in the bath. The bath should also preferably be freefrom ferric compounds in suspension, since these have a tendency to cause the resulting eleetrodeposited metal to be rough.

One method of freeing the bath from ferric compounds, particularly such. compounds in solution, is to add to the bath an oxidizing agent, such as hydrogen peroxide, which will fconvert the dissolved ferric, compounds initially present in the bath into insoluble ferric compounds, which will be precipitated from the bath when the solution is nearly neutral and will collect as a sludge at the .bottom of the bath, while converting the iron content of the anode into a hydrate or other insoluble compound which remains on the anode as a relatively adherent paste, This method and associated means for accomplishing the intended purpose have been described and claimed in one of my pending applications bearing Serial No. 189,852, filed August 4, 1921, and entitled Means for electrodepositing metals.

I have discovered that the same general result, differing, however, in certain important respects both as to the method and means employed and the product resulting from the use of such method and means, may be obtained by having present in the electro'deposition bath a reducing agent, preferably an organic reducing agent, such as oxalic acid,

'pyrogallie acid or'hydroquinone,'but more especially the last compound designated. I prefer to use hydroquinone since this compound appears to be more efiective for the intended purpose and to last longer. In fact, this substance appears to go through a cycle of successive oxidations and reductions dur ing electrolysis. During this cycle the substance appears first to be oxidized at the anode to quinone and thus to act as an oxygen depolarizer to prevent the oxygen generated at'the anode from maintaining the iron compound in solution or suspension in the ferric condition, The quinone thus formed apparently then travels to the cathode where it acts as a hydrogen depolarizer so as to be reconverted into hydroquinone, water being formed at the same time. The'residual hydroquinone or other reducing agent present in the bath during electrolysis acts to reduce any ferric salts formed in the bath to the ferrous condition and to maintain in the ferrous condition any salts initially present in the bath in such condition.

F or the more successful use of the method and means of the present invention, in the production of the product of the present invention, it is desirable that an anode be employed which has a solubility of substantially 100%, so as to prevent the formation in the bath during electrolysis of free sulphuric or other acid from the salts present in the bath, with the consequent production of soluble ferric compounds and a resultant badly pitted .electrodeposit. I- prefer, therefore, to use either the nickel anode described and claimed in my pending application bearing Serial No. 388,812, filed June 14, 1920, and entitled Anodes and method of preparing the same, this anode being prepared under reducing conditions and being substantially free from oxygen but containing a substantial amount of carbon; or else the highly oxidized nickel anode described and claimed in a copending application filed of even date herewith, bearing Serial No. 647,752, and entitled Anodes and material for and method of fabricating the same. By the use of either of these anodes, each of which has a solubility'of substantially 100%, preferably in combination with the other features of this invention, a newand superior type of nickel metal is produced, due in part to the absence of other acids than the acid nickel salt or salts themselves.

Electrodeposition is now effected in the usual manner by the use of the bath containing the fluorine compound of nickel, or its equivalent, and the hydroquinone, or its equivalent, and with-either the carbon-con-. taining or the highly oxi'dized nickel anode described above, preferably the latter. The choice of which of these two types of anodes is to be used depends upon the amount of iron which it is desired that the new type of hard nickel, or its equivalent, shall-contain. Where a metal is desired to be made which is properly classifiable in the category of the true nickel metals, as distinguished from the nickel metal-iron alloys, the

iron present in the cathode is really not desired there, but occurs as an unpreventable and accidental impurity in the electrodeposit resulting from the practice of the invention, In such a case the highlyoxidized anode is preferred, since it contains an exceedingly taining appreciable amounts of iron, .over and above what would ordinarily be present in they electrodeposit as a result of the accidental and unpreventable amounts of iron electrodeposited with the nickel under the conditions set forth above, the carbon-containing anodes are preferred. These anodes generally contain appreciable amounts of iron, since it has not been found feasible in ordinary practice to make such anodes with an iron content of less than A of one per cent. ,Qf course,'more iron than this may be added or may otherwise be present in such an anode, which may be desired Where the electrodeposit is intended to containfrom to 10 per cent of iron, or even more.

The process, as just outlined, is characterized by its complete dependability and entire certainty in operation, the ease and economy with which it may be practiced, and the continuity of such operation over unlimited periods of time, all of these factors rendering it. very practical and commercially very valuable, as contrasted with the processes of the prior art which are discontinuous, requiring frequent ieadj-ustments and doctorings of the bath. The present process is further characterized by the superior and remarkably new and unexpected properties of the resulting electrodeposited metals and metal allows, particularly the nickel metaliron, such as nickel-iron alloys referred to above.

The resulting product is a new type of nickel metal or nickel metal-iron, such as nickel-iron alloy, having very remarkable properties. This metal is mechanically perfect, being free from pores, pits, bunkles and. other mechanical imperfections. If deposited on a polished nickel or nickel-coated cathode, which has preferably been treated for separation by being momentarily employed as an anode in a bath of caustic soda or equivalent substance such as caustic potash, the electrodeposited nickel metal may be removed in the form of a sheet or equiv-v alent body, one side of which substantially reproduces the mirror surface of the oathode upon which it has been deposited, and has thus abrilliant, smooth, mirror-like surface, while the other side has a smooth,

satin-like finish, although, as apparent from thi description, the sheet having these remarkable mechanical properties has not been subjected to any mechanical treatment whatsoever to obtain this remarkable and important result.

This metal, and especially the electrodeposited nickel-iron alloy containing about 0.5 per cent of iron, while being quite hard,

having usually a Brinell hardness from about 182 toabout 236, as contrasted with the Brinell hardness of the soft variety of.

my electrodeposited mechanically perfect the soft variety of my. nickel.

nickel referred to above, which is generally about 112, is quite ductile and may be worked readily and to a considerable extent without any heat treatment. In fact, it is sufficiently ductile to stand about the same amount of cold work as ordinary Bessemer steel or brass without embrittlement. It is also remarkably strong, having a tensile strength substantially in excess of 72,000 pounds per square inch, the average tensile strength of the soft variety of my electrodeposited nickel. In 'fact it often possesses a tensile strength as high as 125,000, or even 136,000, pounds per square inch, or more, depending on itsexact composition and the exact conditions SUlIOUIldlIlg its formation.

- The present or hard variety of my electrodeposited mechanically perfect nickel, however, shows a tendency to become coldshort or slightly brittle after annealing or other heat treatment, as distinguished from v This is probably due to the fact that under the conditions surrounding its electrodeposition the metal apparently contains a substantial amount or percentage of hydrogen, probably amounting to from about 0.01 to about 0.10% of hydrogen which is probably in the combined condition. The metal also contains, as stated above, a substantial amount or percentage of iron, usually from about 0.10 to about 0.50%, although this amount may be increased up to 1.00%, or even much higher. This is due to the fact that the salts used in the bath, and also the anode itself, generally contain substantial amounts of iron which, under the conditions governing the electrodeposition, is maintained in the ferrous condition in the bath and is thus electrodeposited out with the nickel metal,

such as the nickel or its equivalent. In fact the hardness of the nickel metal deposit, particularly the nickel metal-iron alloys or metal mixtures specified above maybe controlled within remarkably wide limits by controlling the percentage of iron present in the deposit. This may readily be done by selecting an anode having the desired percentage of iron in it, an expedient that could not be adopted in the prior artdue to the impossibility of controlling the amount of ferric compound which Would be formed and the presence of which in the bath would result in avery imperfect and practically useless character of deposit.

What I claim as my invention is: i

1. The method of electrodepositing nickel .metals which comprises using a nickel metal electrodeposition bath containing an "iron compound or compounds and maintaining the bath during electrodeposition substantially free from iron compounds in the ferric, condition, whereby the deposited metal is substantially free from pits.

2. The method of electrodepositing nickel metals which comprises using a nickel metal electrodeposition bath containing an iron compound or compounds and maintaining the bath during electrodeposition substantially free from soluble iron compounds in the ferric condition, whereby the deposited metal is substantially free from pits.

3. The method of electrodepositing nickel metals which comprises using a nickel metal electrodeposition bath containing an iron compound or compounds and maintaining the bath during electrodeposition substantially free from insoluble iron com- 1 pounds in the ferric condition, whereby the deposited metal is substantially free from pits.

4:. The method of electrodepositing nickel metals from an electrodeposition bath containing an iron compound or compounds which comprises maintaining such iron compound or compounds in the ferrous condition whereby the deposited metal is substantially free from pits.

5. The method of electrodepositing nickel metals from an electrodeposition bath containing an iron compound or compounds which comprises converting such iron compound or compounds into, and maintaining the same in, the ferrous condition whereby the deposited metal is substantially free from pits.

6. The method of electrodepositing nickel metals from an electrodeposition bath containing an iron compound or compounds which comprises converting such iron compound or compounds into, and maintaining the same in, the ferrous condition by means of a reducing agent present in the electrodeposition bath whereby the deposited metal is substantially free from pits.

7. The method of electrodepositing nickel metals from an electrodeposition bath containing an iron compound or compounds which comprises maintaining such iron compound or compounds in the ferrous condition by means of a reducing agent present in the electrodeposition bath whereby the deposited metal is substantially free from pits.

& The method of electrodepositing nickel metals from an electrodeposition bath containing an iron' compound or compounds which comprises maintaining such iron compound or compounds in the ferrous condition by means of an organic reducing agent present in the electrodeposition bath whereby the deposited metal is substantially free from pits.

9. The method of electrodepositing nickel metals from an electrodeposition bath containing an iron compound or compounds which comprises converting such iron compound or compounds into, and maintaining the same in, the ferrous condition by means of an organic reducing agent present in the electrodeposition bath whereby the deposited metal is substantially free from pits. '10. The method of electrodepositing nickel metals from an electrodeposition bath containing an iron compound or compounds which comprises converting such iron compound or compounds into, and maintaining the same in, the ferrous condition by means of hydroquinone present in the electrodeposition bath whereby the deposited metal is substantially free from pits.

11. The method of electrodepositing nickel metals from an electrodeposition electrodeposition substantially free from iron.

compounds in the ferric condition, whereby the deposited metal is substantially free from pits.

13. The method of electrodepositing nickel metals, which comprises using a nickel metal electrodeposition bath containing a soluble fluorine compound and a soluble an iron compound or compounds, and maintaining the bath during electrodeposition substantially free from iron compounds in the ferric condition, whereby the deposited metal is substantially free from pits.

14. The method of electrodepositing nickel metals, which comprises using a nickel metal electrodeposition bath containing a soluble fluorine compound and a soluble organic reducing agent and containing also an iron compound or compounds, and maintaining the bath during electrodeposition substantially free from iron compounds in the ferric condition, whereby the deposited metal is substantially free from pits.

15. The of method electrodepositing nickel metals, whichcomprises using anickel metal electrodeposition bath containing a soluble fluorine compound and hydroquinone in solution and containing also an iron compound or compounds, and maintaining the bath during electrodeposition substantially free from iron compounds in the ferric condition, whereby the deposited metal is substantially free from pits.

16. Themethod of continuously electrodepositing nickel metals which comprises passing current from a substantially completely soluble nickel metal anode, containing a substantial percentage of iron,

reducing agent and containing also through an electrodepoisition bath substan-,

taining a substantial percentage of iron,

through an electrodeposition bat-h substantiall free'from iron compounds in the ferric -con ition bycontaining an iron compound or compounds in the ferrous condition;

18. The method of continuously electrodepositing nickel metals which comprises passing current from a substantially completely soluble nickel metal anode, containing a substantial percentage of iron,

through an electrodeposition bath substantially free from iron compounds in the ferric condition and containing a fluorine compound and hydroquinone in solution.

19. The method of continuously electrodepositing nickel metals. which comprises passing current from a substantially completely soluble nickel metal anode, containing a substantial percentage of iron, through an electrodeposition, bath substantially free from iron compounds in the ferric condition and containing a fluorine compound and an organic reducing agent in solution.

20. The method ofcontinuously electrodepositing nickel metals Which comprises passing current from a substantially completely soluble nickel metal anode, containing a substantial percentage of iron,

through an electrodeposition bath substantially free from soluble and insoluble iron compounds in the ferric condition by containing anlron compound or compounds in theferrous conditio i 21. Anelectrolyte for the electiodeposit'ion of nickel metals comprising a nickel metal electrodeposition bath substantially free from iron compounds in the ferric condition and containing a soluble compound of fluorine.

22.'An electrolyte for the electrodeposition of nickel metals comprising a nickel metal electrodeposifion bath substantially free from iron compounds in the ferric condition and 'containinga soluble compound of fluorine and a soluble reducing agent.

23. An electrolyte for the electrodeposition of nickel metals comprising a nickelmetal electrodeposition bath substantially free-from iron compounds in the ferric condition and containing a soluble com ound of fluorine and a soluble organic re ucing agent.

' 24:. An electrolyte for the electrodeposition of nickel metals comprising a nickel ing pitless, ductile, malleable and substan tially free from pores and pits, said nickel metali-iron alloy having'a Brinell hardness substantially in excess of- 112.

28. As an article of manufacture, an electrodeposited nickel metal-iron alloy containing a substantial percentage of iron and being pitless, malleable and substantially free from ores and pits, said nickel metal-i'ron al oy having a Brinell hardness from about 182 to about 236.

29. As an article of manufacture, an electrodeposited nickelmetal-iron alloy being pitless, malleable and substantially free from pores and pits, said nickel metaliron alloy having a tensile strength substantially in excess of 72,000 pounds per square inch. V 30. As an article of manufacture, an electrodep osited nickel metal-iron alloy containing a substantial percentage of iron and being pitless, malleable and substantially free from pores and pits, said nickel metal-1ron alloy having a tensile strength sub-- 32. As an article of manufacture,=an elec-' trodeposited nickel n1etal-iron alloy containing a substantial percentage of iron and being pitless, malleable and substantially free from pores and pits, said nickel-metal-iron alloy having a Brinell hardness from about 182 to about 236 and a tensile strength in excess of 125,000 pounds per square inch. 7

In testimony, whereof, I have signed my name-to this specification this '23rd'day of I June, 1923.

, CHARLES P. MADSEN. 

